The field of the invention is pressure vessels used to contain gas under pressure. More specifically, the invention relates to a foam insert for use in connection with pressure vessels to reduce likelihood of flare out when gas contained in the vessel is a flammable material.
It is known that the use of open cell foam inserted into a pressure vessel may reduce the likelihood of dangerous flare out when the pressure vessel carries flammable material. U.S. Pat. No. 5,285,916 to Ross describes the benefits and safety advantages resulting from the use of a foam insert. The Ross patent further sets forth in detail the state of the art at that time of various pressure vessel products.
In the actual assembly and filling of pressure vessels, it has been learned that the foam insert may cause problems. The foam insert can block the easy insertion and mounting of a valve mechanism onto a pressure vessel. Depending on the size of a given valve, and specifically its stem component, and the amount of the foam insert, the foam may abut the stem and block or make difficult the mounting of the valve onto a container having a foam insert. The foam cylinder may also interfere with the proper sealing of the valve to the can.
Accordingly, it is an object of the present invention to provide a foam insert that overcomes the assembly and filling problems noted earlier. The foam insert incorporates a recess that is adapted to receive the inside components of a valve assembly that is mounted onto a pressure vessel.
In one embodiment, a foam insert is adapted for use in combination with a pressure vessel. The insert comprises a cylinder comprised of an open cell foam, the cylinder sized to fit within the pressure vessel. The cylinder comprises a top portion and a bottom portion that correspond to a top and bottom of the pressure vessel. The top portion of the cylinder comprises a concave recess. Additionally, the bottom portion of the cylinder may comprise a concave recess. The recess may extend across the width of the top of the cylinder. The recess may have a v-shaped cross section or a u-shaped cross section or be a blind hole. The foam may be a reticulated open-cell foam. The foam may be flexible. The foam may have a rectangular shape. The pressure vessel may be an aerosol can. The depth of the recess in the insert is in the range of about xc2xc inch to 1 inch depending on valve housing length, preferably about xc2xe of an inch for a typical valve housing.